Surveying instrument.



B. E. GRAHAM.. sUVEYING INSTRUMENT.

' APPLIOATION PILED MAY 12, 1910.

1,023,373. V V Patented Apr. 16, 1912.

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E. E. GRHAM.

SURVEYING INSTRUMENT.

APPLIOATION PILED MAY 12, 1910.

Patented Apr. 16, 1912.

3 SHEBTS-SHEET 2.

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E. E. GRAHAM.

SUBVEYING IN STRUMENT. APLIoAnoN I'ILED MAY 12, 1910.

1,023,373. Patented A pr; 16, 1912.

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EMERY E. GRAI-IAM, OF DENVER, C'OLORADO.

SURVEYING INSTRUMENT.

Specification of Letters Patent.

Patented Apr. 16, 1912.

Application filed May 12, 1910. Seral No. 560,863.

To all whom it may concern Be it known that I, EMERY E. GRAHAM, acitizen of the United States of America, residing at Denver, in thecounty of Denver and State of Colorado, have invented certain new anduseful Improvements in Surveying Instruments, of which the following isa specification.

This invention relates to certain new and useful improvements insurveying instruments of the stadia type and its Object resides in theprovision of an appliance of simple construction by means of which thehorizontal distance and the difference in elevations between theinstrument anda stadia rod may be determined directly by readings on therod, and without reference to the angle of inclination and computatontables.

With the stadia instruments at present in use, the intercept, that isthe space read on v the rod between the stadia-hairs when the telescopeis inclined, denotes 1/100 of the diagonal distance between theinstrument and the rod or with other words, the distance measured alongthe line of collimation of the telescope, and the true distance measuredalong a. horizontal line, or the vertical distance, z'. e. thedifference in elevation between the instrument and the rod, can becletermined only by a calculation in which the said intercept and theangle of inclination of the telescope are factors.

The formulas most frequently employed are for the horizontal distance11:71 cos. A+C cos. A and for the vertical distance V=i-1- sin. 2A+Csin. A

in which Azthe angle of inclination of the telescope read on thevertical circle, i:the

intercept, and C the Constant for the instrument. p

In my inventon the above mentioned calculations are eliminated byautomatically with the telescope, has a sight which when the latter isin its horizontal position, eX- tends opposite to the above mentionedline of zero and which when the telescope is rotated about itst-ransverse axis, moves from the said line along the curved linesextendmg oppositely therefrom.

The refractive appliance is constructed to project an image of theportion of the stationary surface opposite its sight, into the field ofthe telescope and inasmuch as the spaces between: the curved lines atconsecutive points of distance from the line of zero vary in accordancewith the different angles of inclination with which the said pointsagree, the space between the images of the lines and, in consequence,the intercept on the rod viewed through the telescope will varyproportionately. The stadia curves on the stationary surface, arearranged in two pairs, the outer ones of which converge from the zeroline and are designed to correctly designate the horizontal distancesbetween the instrument and the rod, while the inner ones diverge fromthe saidline and denote the vertical distances or diiferencesinelevation. The distance between the outer cu rves at the zero point,herein'after called the curve interval correspondswiththe stadiainterval although it is not necessarily equal thereto and the said outercurves are constructedgzso that the, distance between them at any givenpoint is equal to the curve interval multiplied by cosf A, where A isthe angle through which the sight of. the refractive appliance mustmovein' traveling from the zero line to the given point. The construction ofthe inner curveswhich are designed to denote vertical distances betweenthe instrument and the rod, is Similar to that for the outer curves, thedistance between them at` any given point being equal to the curveinterval multiplied by sin. 2A, where A is the same as above. It

will be understood that the stadiainterval above referred to is thedistance between the stadia hairs as at present employed.

In addition to the lines above described, I denote upon the surface uponwhich they are delineated, at consecutive points, two series ofnuinerals which respectively designate the values of the constants to beadded to the horizontal \and vertical ,distance for the angles ofinclination with which said points agree, so thatthe said numerals willbe projected into the field together with the portions of the linesopposite to which the sight of the refractive appliance is disposed. Thevalues of the constant for the different angles are determined as usualby multiplying the constant with the cosine of the respective angle forthe horizontal distance and with the sine of the angle for the verticaldistances. It will be understood that the convergent and divergent linesas well as the series of numerals are constructed reversely at oppositesides of the line of zero to adapt the instrument for stadia readings atboth higher and lower elevations.

An embodiment of my invention is illustrated in the accompanyingdrawings in the various views of which like parts are similarlydesignated and in which- Figure 1, represents a side elevation of asurveying instrument with a telescope of the inverting type, equippedwith my appliance. Fig. 2, a fragmentary, partially sectional plan viewof the telescope and adjacent parts comprised in said instrument, Fig.3, a section taken along the line 3-3 Fig. 2, Fig. 1, a transversesection taken along the line 1- 1 Fig. 2, Fig. 5, a fragmentary sectionsimilar to Fig. 2 showing the method of applying my invention to aninstrument having a telescope of the erecting type. Fig. 6, a transversesection along the line 6-6 Fig. 5, Fig. 7, a section taken along theline 7-7 Fig. 5, Fig. 8, an enlarged view of the surface upon which thestadia curves and Constant Values are drawn or engraved and Fig. 9, aview of the field of the telescope showing the appearance of the imageof the curves and numerals relative to a stadia rod. Referring to F igs.1 to 4 inclusive, let the reference numeral 2 designate the normallyhorizontal vernier plate of a surveying instrument and 3 the standardsbetween which a telescope 4 of the inverting type is rotatably supportedby means of trunnions 5. Loosely mounted upon one of the trunnionswithin .an annular depression of the vertical circle 6, is .a circularelement 7 which is adjustably held against rotation by two opposite,axially alined screws 8 which are operatively connected with theadjacent standard 3, to engage opposite sides of a lug 10 which projectsoutwardly from the said element. The latter comprises a hub 7 a which,by means of spokes 7 connects with an annular rim 7 of which the lug 10forms v part and which is provided with a segmental Opening before whicha correspondingly shaped plate 12 is fiXedly secured. Engraved, drawn orotherwise produced upon the inner surface of the plate 12, are thestadia curves and Constant values, the former of which are, ashereinbefore described, arranged in two pairs, while the numerals aredisposed in two series between the outer lines and the edges of theplate. The convergent members of the outer pair of lines which aredesigned to designate the horizontal distances between the instrumentand the stadia rod are in the drawings, indicated by the referencecharacter 13, while the inner,

`divergent lines which are adapted to deterof ground glass, for whichreason the curves c and numerals which are produced upon its innersurface, have been drawn in full lines in Fig. 1. The vertical circle 6,which, as usual, is rigidly secured to a collar 5 on the adj acenttrunnion 5, is formed with a circular Opening 16, which when thetelescope is in a horizontal position, is aXially alined with the centerof the Zero line 15 on the plate 12. Fitted within the o-pening 16, isthe extremity of a laterally project-mg branch 17 of a tube 18 which issecured alongside the telescope 41 parallel to its aXis, and whoseopposite end isclosed by a cap 19 which at its innermost side, is opento connect with an Opening 20 formed in the side of the telescope inproximity to its eyepiece 21. Disposed in the line of intersection ofthe vertical planes passing through the axes of the tube 18 and thetherewith connected branch 17 is a double prism 22, the upper and lowerrefracting surfaces of which rcspectively intersect the aXes of the saidbranch, and of the tube 18. The prism 22 is fiXedly mounted in aU-shaped hanger 23, which is adjustably secured against the innersurface of the branch 17 by means of a screw 2 1 which projects througha slot 25, in the wall of the said branch, into a correspondinglythreaded aperture in the hanger. A prism 26, is secured within the cap19 with one of its faces opposite to the lower refracting face, of thedouble prism 22 while another face is disposed opposite the Opening 20in the telescope and in alinement with a face of a third prism 27 whichbeing disposed .in the field of the telescope is, for convenience,secured in a correspondingly shaped slot in the reticle 28. Interposedbetween the prisms 22 and 26, is a double lens which serves to form theimage of the portion of the plate 12 opposite the orifice of the branch17, which by means of the combination of prisms, is projected into thefield. The members 29 of the double lens are separately mounted in cells30 detachably secured at the opposit-e ends of a sleeve 31 which isslidably fitted in the tube 18. The sleeve 31 into which the cells 30are removably fitted, forms a convenient medium for the adjustment ofthe focal length of the lens combination, for not only can the positionof the sleeve be varied with relation to the tube but the distancebetween the lenses may be readily lessened by reducing the length of thesleeve.

The form of my invention illustrated in F igs. 5 to 7 inclusive, isparticularly adapted for use on surveying instruments having telescopesof the erecting type. The telescope 32 of the instrument has in one ofits ends, a relatively stationary head 33 in which the eye piece 34 isfitted and a reticle 35 is disposed opposite a circular Opening in theside of the telescope, whichr is aXially alined with a Similar Openingin the vertical circle 36. The two openings are connected by a tube 37in which a double lens 38, identical in construction with the onehereinbefore described, is slidably fitted. The construction andarrangement 'of the circular element 39 and the therewith connectedplate 40 is Similar to that described for the form illustrated in Fig. 2and the Opening in the vertical circle, which constitutes the sight ofthe refractive appliance, is disposed opposite the line of zero of thestadia lines on the said plate, when the telescope is in the horizontalposition. A double prism 41, disposed in a correspondingly shaped groovein the recticle 35, serves to reflect an image of the portion of thestadia lines opposite the Opening in the vertical circle 36, into thefield of the telescope. To adjust the position of the prism 41 relativeto the line of collimation of the lens for the purpose of centering theimage relative to the horizontal cross-hair of the instrument, I havemounted the reticle 35 in the end of a sleeve 42 which being slidablyfitted in the telescope 32, may be adjusted longitudinally with relationthereto, by the use of two screws 43 and 44 which being operativelyconnected with the head- 33, and the sleeve 42, are respectively adaptedto move the latter in opposite directions.

In assembling the parts comprised in my invention, the position of thedouble prism 22 in the inverting instrument or of the prism 41 in theerecting instrument, is adjusted by the means provided to that purposeas hereinbefore described, until the image of the portion of the stadialines opposite the sight of the refractive appliance, is Centered in thefield of the telescope or with other words, until the stadia linescomprised in each pair are projected in the field at equal distancesfrom the horizontal crosshair. If the curve interval is larger orsmaller than the stadia interval, the distance between the lenses ortheir position in the carrying tube relative to the stationary surface,is adjusted until the distance between the images of the lines whichdetermine the curve interval, gives the correct rod intercept when theinstrument is in the zero position. By rotating the plate 12, by meansof the adjusting-screws 8, the image of the zero line of the curves, ismoved to coincide clined sight is being taken, the reference charactersa and b designate the vertical and horizontal cross-hairs, c the portionof the stadia rod viewed through the telescope, e and e the position ofthe ordinary stadia hairs, and and g-g the image of the stadia curveswhich respectively indicate on the rod, the horizontal and verticaldistances between the latter and the instrument. It will be observedthat the image is projected to one side of the center of the field forthe purpose of leaving the latter clear for ordinary sighting, and thatby the use of the double prism, the image is proj ected into the fieldin a horizontal position i while the lines on the plate are vertical.

While, by reason of simplicity in. construction of the refractiveappliance, the

production of an inverted image is pref-- erable, it will be understoodthat, if so desired, it may be arranged to project the image in an erectposition.

As the operation of my improved instrument does in no way vary from thatof stadia instruments of ordinary construction and the advantagesderived from my invention as well as the method of determining thevertical and horizontal distances, have been fully explained in thefirst part 'of this specification, no further description is deemed'necessary at this point and I wish it understood that while I haveshown and described my invention in the best form at present known tome, variations in the construction and arrangement of the various partsmay be availed of within the principle of the invention.

What I claim and desire to secure by Letters Patent is:

1. In a surveying instrument, the combination with the rotatorytelescope, of a relatively stationary element, and a refractiveappliance movable with the said telescope, and having a sight opposite asurface of the said element, the said appliance being constructed toproject an image of the portion ofthe said surface, opposite the sight,in the field of the telescope, and the said surface bearing lines whichvary in position at consecutive points in the path of the sight, inaccorclance with the corresponding angles of inclination of thetelescope, said lines being equidistantly disposed at opposite sides ofan imaginary circular line.

`2. In a surveying instrument, the combination with the rotato-rytelescope, of a relatively stationary element and a refractive appliancemovable with said telescope and having a sight opposite a surface of thesaid element, the said appliance being conscope and means for adjustingthe position" structed to project an image of the portion of the saidsurface, opposite the sight, in the field of the telesco e and the saidsurface bearing lines which rom a point opposite to the sight when thetelescope is in a horizontal position, vary in spacing at consecutivepoints in the path of the sight, in accordance with -the correspondingangles o-f inclination of the telescope, said lines being equidistantlydisposed at opposite sides of an imaginary circular line.

3. In a surveying instrunent, the combination with the rotatorytelescope, of a relatively stationary element and a refractive appliancemovable with said telescope and having a sight opposite a surface of thesaid element', the said appliance being constructed to project an imageof the portion of the said surface, opposite the sight, in the field ofthe telescope, and the said surface bearing two pairs of lines whichfrom a zero line opposite to the sight when the telescope is horizontal,vary in spacing at consecutive points in the path of the sight, inaccordance with the corresponding angles of inclination of thetelescope, the lines of one pair being convergent while those of theother diverge from the zero line and the lines comprised in each pairbeing equidistantly disposed at opposite sides of an imaginary circularline.

4. In a surveying nstrument, the combination with the rotatorytelescope, of a relatively stationary element and a refractive appliancemovable with said telescope and having a sight opposite a surface of thesaid element, the said appliance being constructed to project an imageof the portion of the said surface opposite the -sight in the field ofthe telescope and the said surface bearing lines which from a pointopposite to the sight 'when the telescope is in a horizontal position,vary in spacing at consecutive points in the path of the sight, inaccordance with the corresponding angles of inclination of thetelescope, and numbers placed alongside said lines at consecutive pointsin the path of the sight and respectively denoting the values of theconstants for the angles with which said points correspond.

5. In a surveying instrument, the combination with the rotatorytelescope, of a relatively stationary element, a refractive applianceincluding a lens and a prism, movablc with the said telescope, the saidappliance having a sight opposite a surface of said element andconstructed to project an image of the portion of the surface oppositethe sight in the field of the telescope, and the said surface bearinglines which vary in spacing at consecutive points in the path of 'thesight, in accordance with the correof the said prism whereby the saidimage may be centered relative to a determinate line in the field.

6. In a surveying instrument, the combination with the rotatorytelescope, of a relatively stationary element, a refractive applianceincluding a lens and a prism, movable with the said .telescope, the saidappliance having a sight opposite a surface of said element, andconstructed to project an image of the portion of the surface oppositethe sight, in the field of the telescope, the said surface bearing lineswhich vary in spacing at consecutive points in the path of the sight, inaccordance with the corresponding angles of inclination of thetelescope, and the said lens being adjustable relative to the said linebearing surface whereby the size of the said image may be varied. V

7. In a surveying instrument, the combination with the rotatorytelescope, ofa relatively stationary element, a refractive applianceincluding a double lens and a prism, movable with the said telescope,the said appliance having a sight opposite a surface V of said element,and constructed to project an image of the portion of the surfaceopposite the eight, in the field of the telescope, the said surfacebearing lines which Vary in spacing at consecutive points in the path'of the sight, in accordance with the corresponding angles ofinclination of the telescope, the said lens being adjustable relative tothe said surface, and the said members being adjustable for varying thedistance between them, for the purpose set forth.

8. In a surveying instrument the combination with its rotatory telescopeand a therewith connected supporting frame, of a relatively stationaryelement adjacent the latter, a tube connected with said telescope one ofits eXtremities being secured in the said frame opposite a surface ofthe said st-ationary element, a refractive device in the said tubeaclapted to produce an image of the portion of the said surface oppositethe said eXtremity, and a' refiector disposed relative to the saiddevice for projecting said image in the field of the telescope, the saidsurface bearing lines which vary in spacing at consecutive points in thepath of the eXtremity of the said tube, in accordance with thecorresponding, angles of inclination of the telescope.

9. In a surveying instrument the combination with its rotatory telescopeand a therewith connected supporting frame, of a relatively stationaryelement adjacent the latter, a t-ube connected with said telescope oneof its extremities being secured in the said frame opposite a surface ofthe said element, a refractive device in the said tube adapted toproduce an image of the portion of the said surface opposite the saideX- tremity, a reflector disposed relative to the said device forprojecting said image in the field of the telescope, and means foradjusting the angular position of the said element on its aXis, the saidsurface bearing lines which Vary in spacing at consecutive points in thepath of the extrenity of the said tube, in aceordanoe with thecorresponding angles of inclinaton of the telesoope.

10. In a surveying instrument, the combination with the rotatorytelesoope of a relatively stationary element and a refractive appliancemovable with said telescope and Gopies of this patent may be obtainedfor five cents each, by addressing' the Commissioner of Patents.

having a sight opposite a surface of said element, the said appliancebeing constructed to project an image of the portion of the said surfaceopposite the eight in the field of the telescope and the said surfacebearing at consecutive points in the p ath of the eight, numbers whichrespectively denote the Vahes of the constants for the angles with whichsaid points correspond.

In testimony whereof I afiix my signature in presence of two witnesses.r

EMERY E. GRAHAM.

Witnesses G. J. ROLLANDET, Roma G. AINSWORTH.

Washington, D. c.

